In an electronic camera, it is generally known that a color shift occurs in captured image data due to the chromatic aberration of magnification of an imaging optical system. There are known techniques to correct such a color shift through image processing.
For example, patent document 1 describes a technique to correct the chromatic aberration of magnification by detecting color shift at the edge portion of an image and performing image processing based on the detected color shift.
Further, patent document 2 describes a technique to correct the chromatic aberration of magnification by adjusting magnification of each color component of an image and finding the minimum difference between the color components.
Furthermore, patent document 3 describes that the chromatic aberration of magnification is corrected simultaneously with the color interpolation of RAW data. In addition, patent document 3 describes a technique to detect the chromatic aberration of magnification from RAW data by detecting a color shift between the same color components of RAW data obtained by imaging a standard pattern and of reference information (stored in advance) on the standard pattern without chromatic aberration.
Patent document 1: Japanese Unexamined Patent Application Publication No. 2000-299874
Patent document 2: Japanese Unexamined Patent Application Publication No. 2002-344978 (FIG. 1, FIG. 3)
Patent document 3: Japanese Unexamined Patent Application Publication No. 2001-186533 (paragraphs 0063 to 0066)